FastColoredTextBoxNS.ExportToRTF.GetColorTableNumber C# (CSharp) Method

        private int GetColorTableNumber(Color color)
        {
            if (color.A == 0)
                return -1;

            if (!colorTable.ContainsKey(color))
                colorTable[color] = colorTable.Count + 1;

            return colorTable[color];
        }